In the past, as this type of cleaning apparatus, an apparatus for cleaning an inert-gas exhaust system of a single crystal pulling machine, the cleaning apparatus that is configured such that a vacuum pump sucks the inert gas supplied to the pulling machine through an exhaust pipe connected to the single crystal pulling machine and is configured such that one end of a pipe for cleaning is connected to an outlet for cleaning provided in the exhaust pipe, a suction pump for cleaning is connected to the other end of the pipe for cleaning, and the suction pump for cleaning sucks the inert gas or atmosphere in the exhaust pipe in an atmosphere exposure state in the pulling machine, has been disclosed (refer to, for example, Patent Document 1). In this cleaning apparatus, a powder separator for cleaning is provided in the pipe for cleaning between the outlet for cleaning and the suction pump, and the suction flow rate of the suction pump can be adjusted.
In the cleaning apparatus configured as described above, at the time of cleaning of the inert-gas exhaust system of the single crystal pulling machine, after the inside of the pulling machine is exposed to the atmosphere, one end of the pipe for cleaning is connected to the outlet for cleaning, and the suction pump for cleaning is driven. At this time, since the flow rate of the atmosphere introduced into the exhaust pipe of the suction pump is increased in a step-by-step manner or gradually, the dust accumulated in the exhaust pipe or the like is first burned gradually, and, after the dust is burned completely, the dust comes off the exhaust pipe or the like and is separated and captured by the powder separator for cleaning. As a result, it is possible to remove almost all the dust accumulated in the exhaust pipe in a short time with ease and safety without a sudden increase in the temperature and the pressure in the exhaust pipe.
Patent Document 1: JP-A-2000-219591 (claim 1, paragraph [0038], FIG. 1)